Large wind power projects could compound global warming

Wind power alone may not be quite the antidote to climate change it may seem, according to one new study. Research published in the journal Joule shows that large-scale turbine projects cause their own warming, minor compared with warming from greenhouse gas emissions, but considerable when compared to emissions-free solar power. Turbines redistribute heat and moisture in the atmosphere, and researchers found that a large-scale wind project could warm the continental US by as much as 0.24 degrees Celsius, according to ScienceDaily.com.

David Keith and Lee Miller, both applied physicists at Harvard University, modelled a massive wind farm generating all of the power used by Americans, totaling 0.46 terawatts, and the effect it would have had between 2012 and 2014. The concentration of turbines needed to provide that power led to its own warming effect, most pronounced where most of the turbines were located.

The warming effect of wind turbines had been observed in more than ten prior studies. The researchers compared their results to these studies, and found the observed effect was roughly consistent with the earlier findings.

The effect of the project was also compared to projections of solar power’s effect on the climate. At the same rate of energy generation, the climate impact of solar power was roughly ten times smaller than that of wind turbines. However, Miller notes that there are other factors, such as the fact that the land between turbines can still be used for agriculture, whereas solar farms are dense, and leave no room for farms.

“Wind beats coal by any environmental measure, but that doesn’t mean that its impacts are negligible,” said Keith. “We must quickly transition away from fossil fuels to stop carbon emissions. In doing so, we must make choices between various low-carbon technologies, all of which have some social and environmental impacts.”

In reality, emissions reduction will involve a mixture of solar, wind, and geothermal energy sources. However, if wind plays a major role by the end of the century, such research is well worth noting. The researchers found that it would take roughly another century to offset the warming effect with the emissions reductions that wind power will allow.

According to Keith:

“The direct climate impacts of wind power are instant, while the benefits accumulate slowly. If your perspective is the next 10 years, wind power actually has — in some respects — more climate impact than coal or gas. If your perspective is the next thousand years, then wind power is enormously cleaner than coal or gas.”